Added proper http request for clustering.
Fixed data download in heatmap keys.
Merge pull request #390 from jfarid27/fix-clustering

Fix clustering
Merge remote-tracking branch 'upstream/master'
Removed heatmap module (hasn't been part of the build for a while),
moving things out of the api module to the dataset module which has
evolved into something everything will need to depend on anyway. Getting
ready to fix pom dependencies